Barrier coatings for flexible packaging paper

Both octenyl succinate modified and hydroxypropylated corn and potato starches were blended with regular and ethylene modified polyvinyl alcohol to increase the water vapour barrier properties and enhance the flexibility of the starch coatings, in order to accomplish superior barrier performance.

Efficient water vapour barrier

Phase separation between starch and polyvinyl alcohol was studied in detail – both in the solution and in dry draw-down coatings on paper. The barrier performance of the coated paper was evaluated with respect to water vapour transmission rate. Conditions for the creation of a thin surface layer consisting of only one of the pure polymers were identified and discussed in terms of phase separation in solution migration of polyvinyl alcohol to the uppermost surface layer. The phase separation promoted low water vapor transmission rates also with a rather high fraction of starch in the coatings.

The study is published in: Progress in Organic Coatings, Volume 111, October 2017, Pages 13-22